1. Field of the Invention
The present invention relates to a vehicle environment monitoring apparatus, a vehicle environment monitoring program, and a vehicle environment monitoring method for monitoring an environment around a vehicle by detecting a monitored object existing in the environment around the vehicle from an image obtained by a camera (imaging unit) mounted on the vehicle.
2. Description of the Related Art
There is conventionally proposed a vehicle environment monitoring apparatus that uses two cameras mounted on a vehicle to detect a distance between the vehicle and a monitored object according to the principle of trigonometrical survey, based on the displacement (parallax) of image portions of the same monitored object extracted from the images of the environment of the vehicle picked up by the respective cameras.
There is also proposed a vehicle environment monitoring apparatus that extracts an image area of a monitored object by determining that the areas of equal distance from the vehicle constitute an image portion of the same object, and determines a type of the monitored object (pedestrian, man-made structure or the like) based on the extracted image area (see, e.g., Japanese Patent Laid-Open No. 2003-216937). With such a conventional vehicle environment monitoring apparatus, the distance between the vehicle and the monitored object in the environment around the vehicle is calculated, and the image area of the monitored object is extracted, separate from the background image, based on the calculated distance.
When detecting the distance from the monitored object based on the parallax as described above, it is necessary to provide two cameras, which means an increased cost and a complicated structure and also requires a troublesome setting job to ensure precise adjustment of the optical axes of the two cameras.